Then, going from one idea to another, he thought of an observation that he had made, which appeared to prove that with many subjects there is less firmness in the morning than in the evening.  Was this the result of dualism of the nervous centres, and was the human personality double like the brain?  Were there hours when the right hemisphere is master of our will, and were there other hours when the left is master?  Did one of these hemispheres possess what the other lacked, and is it according to the activity of this or that one, that one has such a character or such a temperament?  This would be curious, and would amount to saying that, a lamb in the morning, one might be a tiger at evening.  With him it was a lamb that woke in the morning to be devoured by a tiger during the day.  To which hemisphere belonged the one and the other of these personalities?

He was angry with himself for yielding to these reflections; it was a time, truly, to study this psychological question!  It was of Caffie that he should think, and of the plan which in an instant flashed through his mind in the street, before he decided to pick up this knife.

Evidently things were neither so simple nor so easy as they at first appeared, and to insure the success of his plan a combination of circumstances was necessary, which might be difficult to bring about.

Would not the concierge see him pass?  Would no one go up or down the stairs?  Would Caffie be alone?  Would he open the door?  Might not some one ring after he had entered?

Here was a series of questions that he had not thought of before, but which now presented itself.

He must examine them, weigh them, and not throw himself giddily into an adventure that presented such risks.

He was alone all day, fortunately, and, as in the state of agitation in which he found himself he could not think of work, he gave himself up to this examination.  The stakes were worth the trouble—­his honor and his life.

As soon as he was dressed he went out, and walked straight before him through the streets that were already filled with people.

It was only when he had left the heart of Paris that he could reflect as he wished, without being disturbed each instant by people in a hurry, for whom he must make way, or by others who, reading the newspapers, did not look before them, and so jostled against him.

Evidently the risks were more serious than he had imagined; and, as they loomed up before him, he asked himself whether he should go on.  To suppress Caffie, yes; to give himself up, no.

“If it is impossible—­”

He was not the man to set himself wildly against the impossible:  he should have had a dream, a bad dream, and that would be all.

He stopped, and, after a moment of hesitation, turning on his heel, he retraced his steps.  Of what use was it to go farther?  He had no need to reflect nor to weigh the pro and con; he must give up this plan; decidedly it was too dangerous.